Forensic Science International-Genetics最新文献

{"title":"Trace DNA and its persistence on various surfaces: A long term study investigating the influence of surface type and environmental conditions – Part two, non-metals","authors":"Hilary Arsenault,&nbsp;Agnieszka Kuffel,&nbsp;Patricia Dugard,&nbsp;Niamh Nic Daeid,&nbsp;Alexander Gray","doi":"10.1016/j.fsigen.2024.103151","DOIUrl":"10.1016/j.fsigen.2024.103151","url":null,"abstract":"<div><div>The work presented herein is the second part of a large-scale persistence project aimed at identifying trends in trace DNA persistence. This study aims to show how different environmental storage conditions and target surface characteristics influence the persistence of cellular and cell free DNA (cfDNA) over time. To eliminate variation within the experiment, we used a proxy DNA deposit consisting of a synthetic fingerprint solution, cellular DNA, and/or cfDNA. Samples were collected and analysed from eight non-metal surfaces over the course of 1 year (27 time points) under three different environmental storage conditions. The results of this experiment show that surface characteristics in conjunction with DNA type greatly influence DNA persistence. Variation in the amount of DNA recovered over time was greatly influenced by surface porosity. CfDNA persisted at significantly higher levels on non-porous surfaces, and cellular DNA persisted at higher levels on porous items. Furthermore, statistically significant differences in DNA persistence were found among the items classified as non-porous surfaces and among the items classified as porous surfaces. Additionally, this study showed that the sample storage environment had a larger impact on DNA persistence than previously observed for metal surfaces [1]. When considering DNA type, cellular DNA was shown to persist for longer than cfDNA and persistence as a whole appears to be better when DNA is deposited alone rather than in mixtures. Unsurprisingly, it was found that the amount of DNA recovered from trace deposits decreased over time. However, DNA decay is highly dependent on the surface type and exhibits higher variability at short time points and on porous surfaces. For each of the surfaces tested, DNA persisted 1 year past deposition (in some combination of DNA type and environmental condition), except for wood, on which DNA did not persist in any capacity past four months. This data is intended to add to our understanding of DNA persistence and the factors which affect it.</div></div>","PeriodicalId":50435,"journal":{"name":"Forensic Science International-Genetics","volume":"74 ","pages":"Article 103151"},"PeriodicalIF":3.2,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142515271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"FamLink2 – A comprehensive tool for likelihood computations in pedigrees analyses involving linked DNA markers accounting for genotype uncertainties","authors":"Daniel Kling ,&nbsp;Petter Mostad ,&nbsp;Andreas Tillmar","doi":"10.1016/j.fsigen.2024.103150","DOIUrl":"10.1016/j.fsigen.2024.103150","url":null,"abstract":"<div><div>There is an increasing demand for software that can handle an arbitrary number of linked markers in forensic genetics; primarily with application to inference of relationships and direct matching but also in applications such as ancestry inference and mixture interpretation. With the emergence of sequencing technologies, denser sets of SNP markers are generated and analyzed. Additionally, sequence data of low quality and quantity DNA generate uncertainty about the underlying true genotype. We provide an efficient implementation of a general model for pedigree likelihood computations with genetic marker data using a three-layered approach. The top and first layer is the population model where allele frequencies and population substructure are accounted for. The second layer is the inheritance model which efficiently handles linked markers using an IBD model. The third and bottom layer is the observational level where we model the likelihood of the true genotype given underlying reads as well as parameters for errors. We exemplify the utility of our implementation as well as provide validation according to guidelines established by the ISFG using a combination of two published SNP panels. We demonstrate that computations are feasible for panels encompassing 10,000 markers and we argue that, due to the properties of the underlying algorithm, extending the number of markers will result in a linear increase in computation time. In addition we study the impact of parameters used in our model and suggest some guidelines pertaining to their values. The results demonstrate that a probabilistic model for low coverage sequence read data is needed instead of relying on an a threshold based genotype and applying our general model for inference of relationships on a real case can be superior, i.e. higher information content, to other methods relying on either fixed genotypes with low quality sequence data or simple pair wise relationship tests. In summary, the implementation, FamLink2 (freely available at <span><span>https://famlink.se</span><svg><path></path></svg></span>), can jointly handle genetic linkage, genotype uncertainty and population substructure for an arbitrary pedigree with data for any number of individuals. Whereas the current study will focus on calculations disregarding mutations, FamLink2 has the ability to model mutations for certain built-in pedigrees.</div></div>","PeriodicalId":50435,"journal":{"name":"Forensic Science International-Genetics","volume":"74 ","pages":"Article 103150"},"PeriodicalIF":3.2,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"TigerBase: A DNA registration system to enhance enforcement and compliance testing of captive tiger facilities","authors":"Kyle M. Ewart ,&nbsp;Frankie T. Sitam ,&nbsp;Nur Alizati Nabila Binti Giarat Ali ,&nbsp;Rob Ogden ,&nbsp;Kelly I. Morgan ,&nbsp;Hieu M. Tran ,&nbsp;Thanh P.T. Bui ,&nbsp;Truong Q. Nguyen ,&nbsp;Son G. Nguyen ,&nbsp;Norsyamimi Rosli ,&nbsp;Kitichaya Penchart ,&nbsp;Kanita Ouitavon ,&nbsp;Ross McEwing","doi":"10.1016/j.fsigen.2024.103149","DOIUrl":"10.1016/j.fsigen.2024.103149","url":null,"abstract":"<div><div>The illegal trade in tigers (<em>Panthera tigris</em>) and their derivatives, such as bones, teeth and pelts, is a major threat to the species’ long-term persistence. As wild tiger populations have dwindled, a large proportion of trafficked tiger products now derive from captive breeding facilities found throughout Asia. Moreover, wild tigers have been poached and laundered into captive facilities, then falsely designated as captive-bred. The establishment of a DNA registration system is recognized as a key tool to monitor compliance of captive facilities, support tiger trade investigations and improve prosecution outcomes. Here, we present a standardised wildlife forensic DNA profiling system for captive tigers called <em>TigerBase</em>. <em>TigerBase</em> has been developed in four South-East Asia countries with captive tiger facilities: Malaysia, Vietnam, Thailand and Lao PDR. <em>TigerBase</em> DNA profile data is based on 60 single nucleotide polymorphism (SNP) markers, genotyped using two different TaqMan®-based approaches: OpenArray® chip (capable of genotyping 60 SNPs for 48 samples in a single chip), and singleplex TaqMan® assays (capable of genotyping one SNP for one sample per reaction). Of the 60 SNPs, 53 are autosomal nuclear markers, suitable for individualisation and parentage applications, two are sex-linked markers, suitable for sexing, and five are mtDNA markers, suitable for maternal subspecies identification. We conducted a series of validation experiments to investigate the reliability and limitations of these SNP genotyping platforms. We found that the OpenArray® chip platform is more appropriate for generating reference data given its greater throughput, while the singleplex TaqMan® assays are more appropriate for genotyping lower quality casework samples, given their higher sensitivity and throughput flexibility. Only 19 autosomal nuclear markers were validated as singleplex TaqMan® assays, which generally provides ample power for individualisation analysis (probability of identity among siblings was &lt;6.9 ×10⁻⁴), but may lack power for specific parentage questions, such as determining parentage of an offspring when one of the parent’s genotypes is missing. Further, we have developed pipelines to support standardised SNP calling and decrease the chance of genotyping errors through the use of analytical workflows and synthetic positive controls. We expect the implementation of <em>TigerBase</em> will enhance enforcement of tiger trafficking cases and encourage compliance among captive tiger facilities, together contributing to combatting the illegal tiger trade.</div></div>","PeriodicalId":50435,"journal":{"name":"Forensic Science International-Genetics","volume":"74 ","pages":"Article 103149"},"PeriodicalIF":3.2,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1872497324001455/pdfft?md5=6881f0942099400bbcde3ffb8b82ac69&pid=1-s2.0-S1872497324001455-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Uncertainty in the number of contributor estimation methods applied to a Y-STR profile","authors":"Shota Inokuchi ,&nbsp;Hiroaki Nakanishi ,&nbsp;Aya Takada ,&nbsp;Kazuyuki Saito","doi":"10.1016/j.fsigen.2024.103145","DOIUrl":"10.1016/j.fsigen.2024.103145","url":null,"abstract":"<div><p>Maximum allele count (MAC) and total allele count (TAC) methods are widely used for estimating the number of contributors (NoC) of autosomal short tandem repeat (STR) profile in many forensic laboratories. In this study, we applied NoC estimation methods to mixed Y-STR profiles and evaluated its uncertainty and performance. For the MAC method, as recent Y-STR typing kits involve single- and multi-copy loci, we defined “MAC-single” for use across only single-copy loci and “MAC-multi” for use across only multi-copy loci. We generated a dataset containing 120,000 Y-STR profiles for a one to six-person mixture in silico based on previously reported haplotype frequencies of 27 Y-STR loci in Yfiler Plus for the U.S. population (reported by NIST) and the Henan Han population. The dataset was randomly split into a training set and a test set. The training set was used to construct a TAC distribution (TAC curve), whereas the test set was used to calculate the performance metrics (accuracy, precision, recall, and F1-score). In addition, the effect of the upper limit of NoC considered for estimation on overall accuracy was evaluated. The overall accuracies of MAC-single, MAC-multi, and TAC methods when the upper limit of NoC was set to six-person were 0.7920, 0.4329, and 0.7877 for the U.S. population and 0.8207, 0.4609, and 0.8385 for the Henan Han population. Our results suggest that the MAC-single and TAC methods can estimate the NoC for mixed Y-STR profiles with high levels of accuracy.</p></div>","PeriodicalId":50435,"journal":{"name":"Forensic Science International-Genetics","volume":"74 ","pages":"Article 103145"},"PeriodicalIF":3.2,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142243197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dense SNP-based analyses complement forensic anthropology biogeographical ancestry assessments","authors":"Sammed N. Mandape ,&nbsp;Bruce Budowle ,&nbsp;Heather McKiernan ,&nbsp;Donia Slack ,&nbsp;Sarah Mittelman ,&nbsp;Kristen Mittelman ,&nbsp;David Mittelman","doi":"10.1016/j.fsigen.2024.103147","DOIUrl":"10.1016/j.fsigen.2024.103147","url":null,"abstract":"<div><p>Identification of unidentified human remains (UHRs) is crucial yet challenging, especially with traditional forensic techniques. Forensic anthropological examinations can yield ancestry estimations; however, the utility of these estimates is limited by the data points that can be collected from partial remains, complexities of admixture, and variation of phenotypic expression due to environmental effects. While it is generally known that anthropological estimates can be imprecise, the performance of these methods has not been studied at scale. Genome-wide SNP testing is an orthogonal approach for estimating ancestry and offers a unique opportunity to measure the magnitude of anthropological ancestry misattribution. Genomic ancestry inference leverages principal component analysis (PCA) and model-based clustering approaches. This study compares anthropologically determined ancestry with those estimated using genome-wide SNP markers. A dataset of 611 UHR samples with publicly available ancestry assessments from National Missing and Unidentified Persons System (NamUs) was analyzed. The genetic ancestry approach, validated against reference population samples, offers robust ancestry calculations for major population groups. Inconsistency between anthropological and genomic ancestry assignments were observed, particularly for admixed populations. Although forensic anthropological examinations remain valuable, their limitations emphasize the need for refinement and enhancement through the augmentation of SNP-based analyses. Further validation studies are crucial to define the uncertainty associated with both anthropological and genome-based ancestry estimates to resolve cases and aid law enforcement investigations. Additionally, current policy and practices for reporting ancestry for UHRs should be revisited to reduce potential misinformation.</p></div>","PeriodicalId":50435,"journal":{"name":"Forensic Science International-Genetics","volume":"74 ","pages":"Article 103147"},"PeriodicalIF":3.2,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1872497324001431/pdfft?md5=a4661d81cb6b7f5e384265a3077733b5&pid=1-s2.0-S1872497324001431-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142172822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance comparison of a previously validated microhaplotype panel and a forensic STR panel for DNA mixture analysis","authors":"J. González-Bao ,&nbsp;A. Mosquera-Miguel ,&nbsp;L. Casanova-Adán ,&nbsp;A. Ambroa-Conde ,&nbsp;J. Ruiz-Ramírez ,&nbsp;A. Cabrejas-Olalla ,&nbsp;M. Boullón-Cassau ,&nbsp;A. Freire-Aradas ,&nbsp;A. Rodríguez-López ,&nbsp;C. Roth ,&nbsp;R. Lagacé ,&nbsp;C. Phillips ,&nbsp;M.V. Lareu ,&nbsp;M. de la Puente","doi":"10.1016/j.fsigen.2024.103144","DOIUrl":"10.1016/j.fsigen.2024.103144","url":null,"abstract":"<div><p>Short Tandem Repeats (STRs) are the most widespread markers in forensic genetics. However, STR stutter peaks can mask alleles from a minor contributor when analysing mixtures, hindering the interpretation of complex profiles. In this study we compared the performance of a previously described panel of microhaplotypes (MHs), an alternative type of forensic marker, against a standard STR kit. The parameters evaluated included: capability of determining the minimum number of contributors in the mixture; percentages of allele drop-outs and drop-ins; retrieval of alleles belonging to the minor contributor, and estimation of likelihood ratio (LR) values. In addition, the capacity of EuroForMix software to estimate each donor’s percentage of contribution was tested, as well as the impact on results when using manually, or automatically prepared libraries. The MH panel showed better performance than STRs for the detection of 2-contributor mixtures, but the lower degree of polymorphism per MH marker hindered the task of deconvolution with multiple contributors. MHs presented higher drop-in rates and lower drop-out rates, a higher capability to recover the minor contributor’s alleles and provided higher LR values than STRs, likely due to the much higher number of loci combined in the panel. Estimations of contributor ratios using EuroForMix showed promising results and marginal differences were found in these values between manually and automatically prepared libraries. Overall, results showed that the mixture detection performance of the MH panel was better or equal to the standard forensic autosomal STR panel, indicating microhaplotypes are informative markers for this purpose.</p></div>","PeriodicalId":50435,"journal":{"name":"Forensic Science International-Genetics","volume":"74 ","pages":"Article 103144"},"PeriodicalIF":3.2,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1872497324001406/pdfft?md5=091e33948eaa97d39c1fbf587274acaf&pid=1-s2.0-S1872497324001406-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142172821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shotgun DNA sequencing for human identification: Dynamic SNP selection and likelihood ratio calculations accounting for errors","authors":"Mikkel Meyer Andersen ,&nbsp;Marie-Louise Kampmann ,&nbsp;Alberte Honoré Jepsen ,&nbsp;Niels Morling ,&nbsp;Poul Svante Eriksen ,&nbsp;Claus Børsting ,&nbsp;Jeppe Dyrberg Andersen","doi":"10.1016/j.fsigen.2024.103146","DOIUrl":"10.1016/j.fsigen.2024.103146","url":null,"abstract":"<div><p>Shotgun sequencing is a DNA analysis method that potentially determines the nucleotide sequence of every DNA fragment in a sample, unlike PCR-based genotyping methods that is widely used in forensic genetics and targets predefined short tandem repeats (STRs) or predefined single nucleotide polymorphisms (SNPs). Shotgun DNA sequencing is particularly useful for highly degraded low-quality DNA samples, such as ancient samples or those from crime scenes. Here, we developed a statistical model for human identification using shotgun sequencing data and developed formulas for calculating the evidential weight as a likelihood ratio (<span><math><mrow><mi>L</mi><mi>R</mi></mrow></math></span>). The model uses a dynamic set of binary SNP loci and takes the error rate from shotgun sequencing into consideration in a probabilistic manner. To our knowledge, the method is the first to make this possible. Results from replicated shotgun sequencing of buccal swabs (high-quality samples) and hair samples (low-quality samples) were arranged in a genotype-call confusion matrix to estimate the calling error probability by maximum likelihood and Bayesian inference. Different genotype quality filters may be applied to account for genotyping errors. An error probability of zero resulted in the commonly used <span><math><mrow><mi>L</mi><mi>R</mi></mrow></math></span> formula for the weight of evidence. Error probabilities above zero reduced the <span><math><mrow><mi>L</mi><mi>R</mi></mrow></math></span> contribution of matching genotypes and increased the <span><math><mrow><mi>L</mi><mi>R</mi></mrow></math></span> in the case of a mismatch between the genotypes of the trace and the person of interest. In the latter scenario, the <span><math><mrow><mi>L</mi><mi>R</mi></mrow></math></span> increased from zero (occurring when the error probability was zero) to low positive values, which allow for the possibility that the mismatch may be due to genotyping errors. We developed an open-source R package, <span>wgsLR</span>, which implements the method, including estimation of the calling error probability and calculation of <span><math><mrow><mi>L</mi><mi>R</mi></mrow></math></span> values. The R package includes all formulas used in this paper and the functionalities to generate the formulas.</p></div>","PeriodicalId":50435,"journal":{"name":"Forensic Science International-Genetics","volume":"74 ","pages":"Article 103146"},"PeriodicalIF":3.2,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S187249732400142X/pdfft?md5=21c59d83082c09c3567c36aad86c5b15&pid=1-s2.0-S187249732400142X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142172820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The role of cats in human DNA transfer","authors":"Heidi Monkman ,&nbsp;Roland A.H. van Oorschot ,&nbsp;Mariya Goray","doi":"10.1016/j.fsigen.2024.103132","DOIUrl":"10.1016/j.fsigen.2024.103132","url":null,"abstract":"<div><p>Domestic animals, such as cats and dogs, are present in the majority of Australian households. Recently, questions regarding the possibility that domestic animals can serve as silent witnesses, from whom evidence can be collected, or act as vectors of contamination and transfer, have started to be raised. Yet, little is known regarding the transfer and prevalence of human DNA to and from cats. This study investigated if cats are reservoirs and vectors for human DNA transfer. Twenty cats from 15 households were sampled from 4 different areas (head (fur), back (fur), left (skin) and right (fur)) to obtain information on the background DNA that may be found on an animal. Further, transfer of human DNA to and from an animal, after a short patting contact, was tested. Human DNA was found to be prevalent on all cats. Of the areas sampled, most DNA was collected from the top of the fur from the back followed by the head and right/fur. No or very low quantities of human DNA was recovered from the left (skin) area. Most of the human DNA originated from the owners, but DNA from others was also often present (47 % of samples). Further, the transfer tests demonstrated that human DNA transferred readily to (detected in 45 % of samples) and from (detected in 80 % of samples) cats during patting. These results show that animals can act as reservoirs of human DNA and vectors for human DNA transfer that may need to be considered during evaluative DNA reporting. Furthermore, if an interaction between an animal and a perpetrator is suspected, consideration should be given to collecting DNA evidence from suspected contact areas on an animal.</p></div>","PeriodicalId":50435,"journal":{"name":"Forensic Science International-Genetics","volume":"74 ","pages":"Article 103132"},"PeriodicalIF":3.2,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1872497324001285/pdfft?md5=3dc3013ec1b088fdd77c512db8f346a4&pid=1-s2.0-S1872497324001285-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142147182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring legal age estimation using DNA methylation","authors":"M. Boullón-Cassau ,&nbsp;A. Ambroa-Conde ,&nbsp;M.A. Casares de Cal ,&nbsp;A. Gómez-Tato ,&nbsp;A. Mosquera-Miguel ,&nbsp;J. Ruiz-Ramírez ,&nbsp;A. Cabrejas-Olalla ,&nbsp;J. González-Bao ,&nbsp;L. Casanova-Adán ,&nbsp;M. de la Puente ,&nbsp;A. Rodríguez ,&nbsp;C. Phillips ,&nbsp;MV. Lareu ,&nbsp;A. Freire-Aradas","doi":"10.1016/j.fsigen.2024.103142","DOIUrl":"10.1016/j.fsigen.2024.103142","url":null,"abstract":"<div><p>Minors (subjects under the legal age, established at this study at 18 years) benefit from a series of legal rights created to protect them and guarantee their welfare. However, throughout the world there are many minors who have no way to prove they are underaged, leading to a great interest in predicting legal age with the highest possible accuracy. Current methods, mainly involving X-ray analysis, are highly invasive, so new methods to predict legal age are being studied, such as DNA methylation. To further such studies, we created two age prediction models based on five epigenetic markers: cg21572722 (<em>ELOVL2</em>), cg02228185 (<em>ASPA</em>), cg06639320 (<em>FHL2</em>), cg19283806 (<em>CCDC102B</em>) and cg07082267 (no associated gene), that were analysed in blood samples to determine possible limitations regarding DNA methylation as an effective tool for legal age estimation. A wide age range prediction model was created using a broad set of samples (14–94 years) yielding a mean absolute error (MAE) of ±4.32 years. A second model, the constrained age prediction model, was created using a reduced range of samples (14–25 years) yielding an MAE of ±1.54 years. Both models, in addition to Horvath’s Skin &amp; Blood epigenetic clock, were evaluated using a test set comprising 732 pairs of 18-year-old twins (N=426 monozygotic (MZ) and N=306 dizygotic (DZ) pairs), representing a relevant age of study. Through analysis of the two former age prediction models, we found that constraining the age of the samples forming the training set around the desired age of study significantly reduced the prediction error (from MAE: ±4.07 and ±4.27 years for MZ and DZ twins, respectively; to ±1.31 and ±1.3 years). However, despite low prediction errors, DNA methylation models are still prone to classify same-aged individuals in different categories (minors or adults), despite each sample belonging to the same twin pair. Additional evaluation of Horvath’s Skin &amp; Blood model (391 CpGs) led to similar results in terms of age prediction errors than if using only five epigenetic markers (MAE: ±1.87 and ±1.99 years for MZ and DZ twins, respectively).</p></div>","PeriodicalId":50435,"journal":{"name":"Forensic Science International-Genetics","volume":"74 ","pages":"Article 103142"},"PeriodicalIF":3.2,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1872497324001388/pdfft?md5=a27f6df0ba85539c0c136678454ec197&pid=1-s2.0-S1872497324001388-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142147180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Really the best of both? Application of an mRNA/miRNA multiplex assay to casework samples, animal samples, and a storage study","authors":"Malte Bamberg,&nbsp;Maria Bruder,&nbsp;Sebastian N. Kunz,&nbsp;Theresa Wöhrle,&nbsp;Peter Wiegand","doi":"10.1016/j.fsigen.2024.103129","DOIUrl":"10.1016/j.fsigen.2024.103129","url":null,"abstract":"<div><p>The identification of body fluids is an important area of forensic genetics. In particular, the susceptibility to degradation of casework samples is of crucial importance, as the traces can often be exposed to different environmental conditions over a long period of time. RNAs especially are used as molecular markers for the identification of body fluids in forensics. Messenger RNAs (mRNAs) show an increased susceptibility to degradation, e.g. under humidity and UV radiation but are highly body fluid-specific. The shorter micro RNAs (miRNAs), however, are less susceptible to degradation, but only a few body fluid-specific markers could be investigated. In this study, a self-developed mRNA/miRNA multiplex assay for capillary electrophoresis from a preliminary study was further adapted and validated. The approach was applied to casework samples, animal samples, and a storage study. The advantages and disadvantages of the mRNA/miRNA assay were investigated in order to review a possible application for forensic casework. Some miRNA markers were also detected in animal samples, which once again underlines the possible non-specificity of miRNAs. In the storage study, the different markers were detected for different lengths of time depending on the body fluid examined. For almost all body fluids, the miRNA markers were still detectable after a period of 35 days under environmental conditions compared to the mRNA markers. The mRNA peaks were often already clearly reduced or no longer detectable after 14 days. The results show the advantage of the new mRNA/miRNA assay compared to established mRNA approaches, especially for older and degraded samples, but the assay has its limitations due to the limited number of specific miRNA markers.</p></div>","PeriodicalId":50435,"journal":{"name":"Forensic Science International-Genetics","volume":"74 ","pages":"Article 103129"},"PeriodicalIF":3.2,"publicationDate":"2024-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S187249732400125X/pdfft?md5=d926e15a0e45775d22405b1768083e18&pid=1-s2.0-S187249732400125X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142147181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}